Hoyo

My 79 928 is having some trouble with the automatic transmission. It started last week. Driving along I noticed that when stepping on the pedal, the engine would just rev up. It seemed like the transmission just went dead. I stopped the car, turned off the ignition and waited 10 sec before I restarted. Then it worked ok for about 2 min before the same happened again. Thinking I was low on ATF, I added some (too much). The 928 was ok for about 1 hr at 80mph, then the same. I then waited 30 min before I carried on, the 928 worked fine. I stopped by the Mercedes automatic experts here in Oslo, Norway. They told me that it could be a "ventilation disk"(??) that was ackting up, this problem could also fix itself. They also recomended me to use the 928 as normal and come back if my problem continued. Well, today it started ackting up again. It is also a tweaking sound from the transmission when I start the 928 (coldstart), plus, transmission will not shift to third before it warms up. Somebody...any ideas?

UPDATE. JANUARY 2

I did as Steve C recommended. When draining the oil...it was Pitch black...ohoh not a good sign.
Got the pan off and...FILLED with crap...
Well, changed the filter..put together..new oil..RIGHT amount.. drive away...fine...for about 15 mins..back to crap. What now? Complete overhaul?
This is a '79 928 with a '82 928S engine.
Should I overhaul the original tranny? Should I try to get hold of a newer trannsmission? Will a newer tranny fit right into this fine piece of machinery from '79?
Any tips, comments, advice or cash would be greately appreciated.

geir

Steve Cattaneo

Hoyo,
The “tweaking sound” you hear is probably oil pump cavitation from oil starvation, due to a clogged transmission filter. Your transmission is failing. I would change the filter; it might extend the life of the trans.


Steve C
The great white

Hoyo

Thank you SC.
The 928 is parked. I'll use the "other" car to get to my brother's family x-mas party tonight.
I will do as advised the next few days and hope for the best.
My time is my own now since my lady split after I bought the Porsche. She despised that car.

"Men, this is no drill."

Hoyo

UPDATE.....JAN. 2 in original posting.

Moss928

Hoyo,

It sounds like that gal may have left you anyway. The car was an excuse (a bad one at that). Think of it this way: You can always find a woman. Finding the right car is difficult, and for everything else there is Visa!

Moss

Randy V

Sounds like your tranny is toast.

Rebuilding yours may be the only option, unless you know of a parts supplier who will sell you a rebuilt one (usually cheaper than having yours rebuilt).

John Struthers

Hoyo,
Sorry, yours is not the language of love - not enough Germanic clues for me -.
To the point. I was surfing the net and hit 'Bildesbasen'. I'm still not sure if I was in the salvage yard section or auto sales.
In any case there were a number of 78's, 79's, 82's, ....
The site I was on was - sorry - Swedish.
actually, I hit on it by looking for Danish auto salvage yards and came up with a Land Rover site - go figure - and eventually, found this area.
My recommendation check the salvage yards before you even think about a transmission rebuild. Stick with the 3speed as the 4 speed requires other parts to make it work so you would need a whole donor car, more than likely.
Start hunting guy! Most of the sharks get nailed in an accident, blow an engine, smoke a brain should be a salvageable 3 speed tranny out there somewhere. Take a look at your torque tube while you are under your sHARk.
Good luck and good hunting!
John S. 82' Weissach, Auto., Pattycakes

Jay Wellwood

You may consider giving 928 International a call - I looked in their Catalog last night - used tranny = $1000, rebuilt = $1995.

This may be an option - but surely not the only one.

hth-

Randy V

I think the freight charges to Norway may be prohibitive Jay.

Jay Wellwood

DOH!

Thanks Randy - I obviously overlooked that minor detail.

Teach me to read a bit closer.....

Steve Cattaneo

Hoyo,

Which ever way you choose, rebuilt or used, you must flush the transmission lines and cooler that is in the radiator. Other wise all of that contamination will just get back into the transmission.

Steve C,
The Great White

Hoyo

Hello again.
Searching the net, I came across a tranny from a '80 928, complete with converter and torque tube, for a nice price.
This tranny comes from a 928 damaged in a collision. The 928 had 85K miles on it.(not in Norway).
Would this be a good solution?
To rebuild my existing tranny will cost me 2500.
Will I have to remove the oil cooler from the radiator when flushing?

Randy V

Others may have different opinions, but if it was me, I'd pay for the rebuild of the trans/torgue converter with a 1 year warranty over buying a used trans that is just as old as the one you need to fix. That rebuild cost most likely includes the labour to remove and replace the transmission. If you buy a used trans you still have to pay somebody to swap them out, unless you plan on doing the job yourself. If the former, the total cost will be similar to that of having the rebuild done.

You should do the torque tube at this time - not much additional labour - mostly the cost of the parts (either replace the bearings or swap with a new/rebuilt one).

The trans cooler lines connect to the passenger side of your radiator - the cooling circuit is part of the internal radiator.